Sen. John McCain said Friday that the tragic shoot-down of Malaysia Airlines Flight MH17 might never have happened if the United States had armed Ukrainian forces battling against Russian-backed separatists.

The Arizona Republican also said there's no reason to wait for an international investigation of the site of the crash in eastern Ukraine.

McCain pinned the blame on Russian President Vladimir Putin, but said the U.S. does have some responsibility for not arming the Ukrainians in their fight against separatists and other Russian elements.

"I think he has to be treated ... as a pariah because it's all his responsibility. Those are Russian separatists which he has supported," McCain said of Putin.

"We are also responsible because when they begged us — the Ukrainians begged us for defensive weapons, we sent the MREs. It's possible that they could've, they could've taken over eastern Ukraine if they'd had the weapons with which to do so," McCain said Friday. "It's shameful."

"I just think this is the consequence of a foreign policy where aggressive people are not met and challenged. I'm not blaming the United States for shooting down the airplane. I'm saying that the foreign policy of President Obama is allowing conflicts to grow in scope and nature," Graham told reporters.

"We don't have to wait for an investigation. This shoot-down was caused by Vladimir Putin, and I'm afraid our European friends again are going to take a hike," McCain said on KYFI radio in Phoenix . "Do you think that the French are going to return Vladimir Putin's money and not send them the two helicopter carriers that they just sold to the Russians? I don't think so."

McCain said that nonetheless it was important to get access to the site in order to provide dignity for the remains of the roughly 300 people who died in the incident.

Senate Majority Whip Richard J. Durbin, D-Ill., said Friday it was critical that there's an open investigation.

"There is increasing evidence that Russian-backed Ukrainian separatists may have been involved in this terrible act. It is critical that the crash site be secured and the crash thoroughly investigated by the international community," Durbin said in a statement. "Russian-backed rebels must not be allowed to manipulate evidence that might implicate their own role in this tragedy."

Durbin's Illinois colleague, Republican Mark S. Kirk, told CNN on Friday that in addition to enhanced U.S. sanctions against Russia, there should also be a wrongful death lawsuit targeting Russian assets in the United States, such as those of the oil giant Lukoil.

"Russia should pay a significant cost inside the United States for this act," Kirk said. "They should always realize tens of millions of dollars will be lost ... because of actions like this, and get control of their armed forces to make sure there is effective command and control."

It was Kirk's first live appearance on cable TV news since a January 2012 stroke that led to an extended absence from the Senate for recovery.